The present invention relates to a mine detector and an inspection apparatus, and more particularly, to a mine detector and an inspection apparatus which can safely and promptly detect land mines, a structure within a concrete wall, and so on.
Recently, in a region where an intestine war or the like took place, a need exists for removing land mines buried in the ground after the termination of the intestine war. Conventionally, land mines have been removed, for example, in the following manner.
First, within a predetermined range, an operation is performed for confirming the presence or absence of trap wires. The trap wires are coupled to the buried ground, such that a walking person touching the trap wire causes a land mine to explore, so that the trap wires are first removed.
Next, within a range where it is confirmed that there are no trap wires, the grass is cut for facilitating an inspection. Then, within the range where the grass has been cut, the presence or absence of land mines is inspected using a metal detector.
When a metal reaction is caught by the metal detector, the operator uses a stick of approximately 30 centimeters long to carefully dig the ground up from that position to confirm whether or not the sensed reaction is due to a land mine. When the existence of a land mine is confirmed, this is dug out, removed, and then carried to a predetermined place where it is explored using an explosive or the like.
On the other hand, for inspecting a structure within a concrete wall, it is known that a state internal to the concrete is detected by transmitting an electromagnetic wave toward the interior of the concrete and receiving a reflected signal therefrom, for example, as previously proposed by one of the applicants as Laid-open Japanese Patent Application No. Hei 9-88351.
Conventionally, since land mines are detected using a metal detector in the manner mentioned above, a problem is encountered in securely detecting the land mines if they are made of other than metals, for example, plastics or the like.
Further, the metal detector is configured to notify the operator of a metal reaction through sound such as xe2x80x9cbeep.xe2x80x9d The sound becomes larger as the metal detector is closer to a metal and smaller as it is further away from a metal. The operator is required to gain experience for identifying the position at which the largest sound is generated. As a result, an operator less experienced with the operation digs the ground up with a stick from a position at which even small sound begins (a position far away from a land mine) for safety, so that a problem arises in that the detection of land mines is time consuming.
Further, when a metal detector is used, nails, other metal fragments and so on, if buried other than land mines, are also detected. Before digging out, it is unknown whether a detected object is a land mine or not, so that the ground must be carefully dug out. However, as a result of digging out over a long time, it is often the case that the object is not a mine.
Consequently, it comes down to a problem in taking a very long time to detect whether or not land mines are buried within a predetermined area to confirm the safety.
Also, as previously proposed, the method of detecting an internal structure within a concrete from a reflected wave of an electromagnetic wave transmitted thereto implies a problem that precise detection of the internal state is difficult due to a difference in the level of the reflected electromagnetic wave, caused by a moisture included in the concrete, and so on.
The present invention has been made in view of the situations as mentioned, and its object is to provide a mine detector which is capable of safely, promptly and reliably detecting land mines buried in the ground.
Also, it is an object of the present invention to provide an inspection apparatus which is capable of promptly and reliably detecting the presence or absence of an object, and the state of an object under inspection.
A mine detector according to the present invention is a mine detector for detecting a land mine buried in the ground, which comprises transmitting and receiving means for transmitting an electromagnetic wave toward the ground of a range intended to detect the land mine for scanning, and receiving a reflected wave thereof, position detecting means for detecting the position of the transmitting and receiving means at a time the transmitting and receiving means receives the reflected wave, an internal ground structure information generating means for generating information indicative of a three-dimensional structure in the ground based on a period of time from the transmission of the electromagnetic wave by the transmitting and receiving means to the reception of the reflected wave, a received level of the reflected wave, and a position detected by the position detecting means, image information generating means for generating image information for display from information indicative of the three-dimensional structure generated by the internal ground structure information generating means, and display means for displaying an image based on the image information generated by the image information generating means.
In this mine detector, information indicative of a three-dimensional structure in the ground is processed based on a period of time until a reflected wave is detected after the electromagnetic wave has been transmitted, a received level of the reflected wave, and a position at which the reflected wave is detected. An image signal for display is generated from the processed information indicative of the three-dimensional structure, thereby displaying an image based on the image signal.
According to this mine detector, since the electromagnetic wave is transmitted and received to generate information indicative of a three-dimensional structure in the ground, from which image information for display is generated and displayed, it is possible to promptly and reliably detect land mines in a wide area.
Another mine detector according to the present invention is a mine detector for detecting a land mine buried in the ground, which comprises transmitting and receiving means for transmitting an electromagnetic wave toward the ground of a range intended to detect the land mine for scanning, and receiving a reflected wave thereof, position detecting means for detecting the position of the transmitting and receiving means at a time the transmitting and receiving means receives the reflected wave, an internal ground structure information generating means for generating information indicative of a three-dimensional structure in the ground based on a period of time from the transmission of the electromagnetic wave by the transmitting and receiving means to the reception of the reflected wave, a received level of the reflected wave, and a position detected by the position detecting means, calibration means for calibrating the value of a dielectric coefficient of the ground which is a parameter for use in the internal ground structure information generating means, image information generating means for generating image information for display from information indicative of the three-dimensional structure generated by the internal ground structure information generating means, and display means for displaying an image based on the image information generated by the image information generating means.
In this mine detector, information indicative of a three-dimensional structure in the ground is processed based on a period of time until a reflected wave is detected after the electromagnetic wave has been transmitted, a received level of the reflected wave, and a position at which the reflected wave is detected. The calibration is performed for the value of the dielectric coefficient as a parameter for use in generating information of the structure in the ground. An image signal for display is generated from the processed information indicative of the three-dimensional structure, thereby displaying an image based on the image signal.
According to this mine detector, since the calibration is performed for the value of the dielectric coefficient to generate information of a three-dimensional image in the ground, it is possible to accurately, promptly and safely detect the position of a land mine.
An inspection apparatus according to the present invention is an inspection apparatus which comprises transmitting and receiving means for transmitting an electromagnetic wave to an object under inspection in a range in which the object under inspection is scanned, and receiving a reflected wave thereof, a position detecting means for detecting a position at which the transmitting and receiving means receives the reflected wave, processing means for processing a signal indicative of a three-dimensional structure inside of the object under inspection based on a period of time from the transmission of the electromagnetic wave by the transmitting and receiving means to the reception of the reflected wave, a received level of the reflected wave, and a position detected by the position detecting means, calibration means for calibrating the processing by the processing means, generating means for generating an image signal from the signal indicative of the three-dimensional structure processed by the processing means, and display means for displaying an image based on the image signal generated by the generating means.
In this inspection apparatus, a signal on a three-dimensional coordinates representative of a state inside of the object under inspection is processed based on a period of time until a reflected wave is detected after the electromagnetic wave has been transmitted, a received level of the reflected wave, and a position at which the reflected wave is detected. After the calibration is performed, an image signal is generated from the processed signal on the three-dimensional coordinates, thereby displaying an image based on the image signal.
According to this inspection apparatus, since the calibration is performed based on the dielectric coefficient to inspect the object under inspection, it is possible to promptly and reliably inspect an article in the object under inspection.
Another inspection apparatus according to the present invention is an inspection apparatus which comprises transmitting and receiving means for transmitting an electromagnetic wave to an object under inspection in a range in which the object under inspection is scanned, and receiving a reflected wave thereof, inspecting means for inspecting the interior of the object under inspection from an output of the transmitting and receiving means, generating means constructed integrally with the transmitting and receiving means for generating at least three light beams, light receiving means for receiving the three light beams and outputting signals corresponding to positions at which the light beams are received, and position detecting means for detecting a position of the transmitting and receiving means from an output of the light receiving means.
In this inspection apparatus, at least three light beams are generated corresponding to the position of the transmitting and receiving means, and the position of the transmitting and receiving means is detected from signals corresponding to positions at which the light beams are detected.
According to this inspection apparatus, since the position of the transmitting and receiving means is detected based on positions at which at least three light beams are received, it is possible to not only detect the three-dimensional position of the transmitting and receiving means but also detect its posture. As a result, the object under inspection can be accurately and promptly inspected.
Other objects, features and benefits of the present invention will become sufficiently apparent from the following description.